In general, there exists a packet pair technique as a conventional example of calculating the communication speed of the communication path that goes through a series of paths (links) and intermediate nodes.
In the packet pair technique, the communication speed of the path, which is comprised of high-speed and low-speed links connecting a transmission node and a reception node, is the object of calculation. The transmission node successively transmits two probe packets (packet pair) dedicated for calculating the speed of the path that is an object of calculation, and the speed of the path is derived from a difference between arrival times of two packets, which arises as a result of transmission. In doing this, so as to limit the cause of arrival time difference between two packets, which is measured at the reception node, to a dispersion of transmission delay between two points alone, the transmission node transmits two packets at as close times as possible.
Further, as another conventional example, i.e. as a conventional example except the packet pair technique, there exists a packet train technique (for example, non-patent document 1).
[Non-Patent Document 1]
Dovrolis, Ramanathan, and Moore, “What Do Packet Dispersion Techniques Measure?” IEEE INFOCOM 2001
The packet train technique, which is a technique of successively transmitting two or more packets, does not necessarily provide a discrete mode of calculation results as in the case of the packet pair technique; nevertheless, a sufficient long measurement duration allows measurement values that converge to a single value.